The Engine Scan Tool Data Definitions contains a brief description of all engine related parameters available on the scan tool. The list is in alphabetical order. A given parameter may appear in any one of the data lists. In some cases, the parameter may appear more than once or in more than one data list in order to group certain related parameters together.

Cold Start Up: The scan tool displays Yes or No. A cold start up is when the engine coolant temperature (ECT) rises above a predetermined temperature during an ignition cycle. The next ignition cycle the engine coolant temperature should be below a predetermined temperature. Also the engine coolant temperature and the intake air temperature (IAT) are less than 50°C (122°F) and are within 3°C (5°F) of each other at start up. When the above is true the scan tool displays Yes.

ECT Sensor:  The scan tool displays a range of -39 to +140°C (-38 to +284°F). The engine coolant temperature (ECT) sensor is mounted in the cylinder head of the left bank. The PCM applies 5 volts to the ECT sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the PCM monitors a high signal voltage and interprets the voltage as a cold engine. As the sensor warms (internal resistance decreases), the voltage signal decreases and the PCM interprets the lower voltage as a warm engine.

Fan Control: The scan tool displays ON or OFF. This parameter indicates if the engine cooling fan low speed relay has been commanded ON or OFF.

Fan Requested: The scan tool displays YES or NO. This parameter indicates if the engine cooling fan low speed relay has been requested ON or OFF.

Fan Run On: The scan tool displays ACTIVE or INACTIVE. This parameter indicates if the engine cooling fan low speed relay has been commanded ON or OFF.

Fan Run On: The scan tool displays 0. This parameter indicates the number of seconds that the engine cooling fan low speed relay has been commanded ON.

FC Relay 1 Command: The scan tool displays ON or OFF. The scan tool displays ON when the PCM commands a coolant fan relay ON. Both fans are enabled on low speed when the PCM commands the fan one relay control ON.

FC Relay 2 Command: The scan tool displays ON or OFF. The scan tool displays ON when the PCM commands a coolant fan relay ON. Both cooling fans are enabled on high speed when the PCM commands both fan control circuits ON.

Low Speed Fan Relay: The scan tool displays ON or OFF. This parameter indicates if the engine cooling fan low speed relay has been commanded ON or OFF.

Start Up ECT: The scan tool displays a range of -39 to +140°C (-38 to +284°F). The scan tool displays the Engine Coolant Temperature at the time the engine was started. The PCM uses Start Up ECT for certain DTCs.